Unlike other biologics that are produced via recombinant expression of DNA vectors in host cell lines, plasma-derived proteins are fractionated from human blood and plasma donations. Thus, the supply of these products cannot be increased by simply increasing the volume of production. Rather the level of commercially available blood products is limited by the available supply of blood and plasma donations. This dynamic results in a shortage in the availability of raw human plasma for the manufacture of new plasma-derived blood factors that have lesser established commercial markets, including Inter-alpha-Inhibitor proteins (IaIp), such as Inter-alpha Trypsin Inhibitor (IaI) and Pre-alpha-Inhibitor (PaI), and Factor H.
Inter-alpha Trypsin Inhibitor (IaI) is a plasma protein that belongs to a family of protease inhibitors (Inter-alpha-Inhibitor proteins; IaIp) with roles in sepsis, cancer metastasis and inflammation (for review, see, Salier, J, et al., Biochem J 315: 1-9 (1996)). IaI has an approximate molecular weight of 225 kDa and is composed of two heavy chains (H1 and H2) and a single light chain (bikunin) polypeptide covalently linked liked by chondroitin sulfate (FIG. 1). Pre-alpha-Inhibitor (PaI) is a related Inter-alph-Inhibitor composed of one heavy chain (H3) and one small chain (bikunin) polypeptide, again covalently linked liked by chondroitin sulfate (FIG. 1). Inter-alpha-Inhibitor proteins (IaIp) are present at levels between about 600-1200 mg/L in adult plasma (Lim et al., J Chromatogr A. (2005) February 11; 1065(1):39-43).
Sepsis is a medical condition characterized by whole-body inflammatory, known as systemic inflammatory response syndrome (SIRS) and the presence of a known or suspected infection. Whole-body inflammation occurring in sepsis is commonly caused by the immune system's response to a bacterial, viral, or fungal infection that has spread throughout the organism via the blood stream. These infections commonly begin in the lungs (pneumonia), bladder and kidneys (urinary tract infections), skin (cellulitis), abdomen (such as appendicitis), and other areas (such as meningitis).
A marked increase in the number of cases of sepsis has occurred over the past 20 years. This increase is due in part to the increased reliance on treatments for cancer and organ-transplant patients with medications that weaken the immune system. Increased average lifespan and an aging world population have also contributed to the increased incidence of sepsis. Furthermore, the development of antibiotic-resistant bacteria has contributed to the number of cases of sepsis.
Studies have shown correlations between decreased plasma levels of IaIp and mortality in patients with severe sepsis (Lim et al., J Infect Dis. (2003) September 15; 188(6):919-26 and Opal et al., Crit Care Med. (2007) February; 35(2):387-92). Furthermore, several studies have shown that the administration of IaIp reduces mortality associated with sepsis and septic shock (Jourdain et al., Am J Respir Crit Care Med. (1997) December; 156(6):1825-33; Yang et al., Crit Care Med. (2002) March; 30(3):617-22; Lim et al., J Infect Dis. (2003) September 15; 188(6):919-26; and Wu et al., Crit Care Med. (2004) August; 32(8):1747-52; the disclosures of which are incorporated by reference herein in their entireties for all purposes). While the relationship between IaIp and sepsis has been characterized, medicaments based on this relationship have thus far not been identified.
Due in part to the increasing global demand and fluctuations in the available supply of plasma-derived blood products, such as immunoglobulin products, several countries, including Australia and England, have implemented demand management programs to protect supplies of these products for the highest demand patients during times of product shortages.
For example, it has been reported that in 2007, 26.5 million liters of plasma were fractionated, generating 75.2 metric tons of IVIG, with an average production yield of 2.8 grams per liter (Robert P., supra). This same report estimated that global IVIG yields are expected to increase to about 3.43 grams per liter by 2012. However, due to the continued growth in global demand for IVIG, projected at between about 7% and 13% annually between now and 2015, more raw plasma will need to be dedicated to immunoglobulin purification to meet the demand in spite of the expected improvement of the overall IVIG yield. This requirement will limit the availability of plasma for the manufacture of new plasma-derived blood products.
Due to the lack of plasma available for the manufacture of new plasma-derived products, their manufacture must be integrated into the existing framework of the established manufacturing processes for plasma-derived products such as immunoglobulins and albumin. Inter-alpha-Inhibitors, implicated as a potential therapeutic for sepsis, among other conditions, is one such plasma-derived blood product that is gaining the attention of physicians. However, due to the resources devoted to, for example, IgG gamma globulin manufacture, methods are needed for the manufacture of IaIp that can be introduced into the existing manufacturing schemes. Several methods have been suggested to achieve just this, however, these methods rely on adsorption of IaIp from source material that is in high demand for the purification of essential products such as IVIG. For example, Michalski et al. (Vox Sang. 1994; 67(4):329-36) and Mizon et al. (J Chromatogr B Biomed Sci Appl., 1997 May 9; 692(2):281-91) describe methods wherein IaIp is adsorbed from cryo-poor plasma by successive anion exchange enrichment steps, followed by heparin affinity chromatography. Josic (U.S. Patent Application Publication No. 2003/0190732) describes a method wherein IaIp is isolated from raw plasma, a cryoprecipitate plasma fraction, or a cryo-poor plasma by size exclusion chromatography and optionally an adsorption step. Finally, Lim et al. ('365; U.S. Pat. No. 7,932,365) and Lim et al. ('695; WO 2009/154695) describe methods wherein IaIp is adsorbed via solid phase extraction from a cryo-supernatant or a cryo-poor-plasma (see, FIG. 8 and FIG. 1 of Lim et al. '365 and '695, respectively). Accordingly, the purification schemes provided by Michalski et al., Mizon et al., Josic, and Lim et al. (the disclosures of which are hereby incorporated by reference in their entireties for all purposes) consume valuable starting material, will require new regulatory approvals for the established products, and/or may even result in alterations of the characteristics of the established products.
As such, a need remains in the art for methods of manufacturing IaIp compositions that do not require the use of additional input plasma or the redesign and regulatory re-approval of existing manufacturing processes for commercially important plasma derived blood products, such as albumin and IgG gamma globulins for intravenous (IVIG) or subcutaneous administration. Advantageously, the present invention fulfills these and other needs by providing methods of manufacturing Inter-alpha-Inhibitor proteins (IaIp) that rely entirely on previously unused manufacturing fractions. Among other aspects, the present invention also provides novel IaIp compositions and methods for treating diseases and disorders associated with IaIp dysfunction or dysregulation. Finally, the present invention provides methods for the co-manufacture of IaIp and Factor H from plasma fractionations otherwise discarded during the manufacture of other blood factor compositions.